scholarly journals TRIM25 and DEAD-Box RNA Helicase DDX3X Cooperate to Regulate RIG-I-Mediated Antiviral Immunity

2021 ◽  
Vol 22 (16) ◽  
pp. 9094
Author(s):  
Sarah C. Atkinson ◽  
Steven M. Heaton ◽  
Michelle D. Audsley ◽  
Oded Kleifeld ◽  
Natalie A. Borg
Keyword(s):  
Influenza A Virus ◽  
Influenza A ◽  
Rna Virus ◽  
In Vitro Assays ◽  
Type I ◽  
Structural Protein ◽  
Host Proteins ◽  
Multiple Substrates ◽  
Dead Box

The cytoplasmic retinoic acid-inducible gene-I (RIG-I)-like receptors (RLRs) initiate interferon (IFN) production and antiviral gene expression in response to RNA virus infection. Consequently, RLR signalling is tightly regulated by both host and viral factors. Tripartite motif protein 25 (TRIM25) is an E3 ligase that ubiquitinates multiple substrates within the RLR signalling cascade, playing both ubiquitination-dependent and -independent roles in RIG-I-mediated IFN induction. However, additional regulatory roles are emerging. Here, we show a novel interaction between TRIM25 and another protein in the RLR pathway that is essential for type I IFN induction, DEAD-box helicase 3X (DDX3X). In vitro assays and knockdown studies reveal that TRIM25 ubiquitinates DDX3X at lysine 55 (K55) and that TRIM25 and DDX3X cooperatively enhance IFNB1 induction following RIG-I activation, but the latter is independent of TRIM25’s catalytic activity. Furthermore, we found that the influenza A virus non-structural protein 1 (NS1) disrupts the TRIM25:DDX3X interaction, abrogating both TRIM25-mediated ubiquitination of DDX3X and cooperative activation of the IFNB1 promoter. Thus, our results reveal a new interplay between two RLR-host proteins that cooperatively enhance IFN-β production. We also uncover a new and further mechanism by which influenza A virus NS1 suppresses host antiviral defence.

scholarly journals MicroRNA-132-3p suppresses type I IFN response through targeting IRF1 to facilitate H1N1 influenza A virus infection

2019 ◽  
Vol 39 (12) ◽  
Author(s):  
Fangyi Zhang ◽  
Xuefeng Lin ◽  
Xiaodong Yang ◽  
Guangjian Lu ◽  
Qunmei Zhang ◽  
...  
Keyword(s):  
Influenza A Virus ◽  
Peripheral Blood ◽  
Influenza A ◽  
Expression Profiles ◽  
Protein A ◽  
H1n1 Influenza ◽  
Type I ◽  
Dependent Manner ◽  
Type I Ifn

Abstract Increasing evidence has indicated that microRNAs (miRNAs) have essential roles in innate immune responses to various viral infections; however, the role of miRNAs in H1N1 influenza A virus (IAV) infection is still unclear. The present study aimed to elucidate the role and mechanism of miRNAs in IAV replication in vitro. Using a microarray assay, we analyzed the expression profiles of miRNAs in peripheral blood from IAV patients. It was found that miR-132-3p was significantly up-regulated in peripheral blood samples from IAV patients. It was also observed that IAV infection up-regulated the expression of miR-132-3p in a dose- and time-dependent manner. Subsequently, we investigated miR-132-3p function and found that up-regulation of miR-132-3p promoted IAV replication, whereas knockdown of miR-132-3p repressed replication. Meanwhile, overexpression of miR-132-3p could inhibit IAV triggered INF-α and INF-β production and IFN-stimulated gene (ISG) expression, including myxovirus protein A (MxA), 2′,5′-oligoadenylate synthetases (OAS), and double-stranded RNA-dependent protein kinase (PKR), while inhibition of miR-132-3p enhanced IAV triggered these effects. Of note, interferon regulatory factor 1 (IRF1), a well-known regulator of the type I IFN response, was identified as a direct target of miR-132-3p during HIN1 IAV infection. Furthermore, knockdown of IRF1 by si-IRF1 reversed the promoting effects of miR-132-3p inhibition on type I IFN response. Taken together, up-regulation of miR-132-3p promotes IAV replication by suppressing type I IFN response through its target gene IRF1, suggesting that miR-132-3p could represent a novel potential therapeutic target of IAV treatment.

scholarly journals Molecular Basis of the Ternary Interaction between NS1 of the 1918 Influenza A Virus, PI3K, and CRK

Viruses ◽  
2020 ◽  
Vol 12 (3) ◽  
pp. 338
Author(s):  
Alyssa Dubrow ◽  
Sirong Lin ◽  
Nowlan Savage ◽  
Qingliang Shen ◽  
Jae-Hyun Cho
Keyword(s):  
Influenza A Virus ◽  
Molecular Basis ◽  
Influenza A ◽  
Host Protein ◽  
Structural Protein ◽  
Host Proteins ◽  
Ternary Interaction ◽  
Important Virulence Factor ◽  
1918 Influenza ◽  
Phosphoinositide 3 Kinase

The 1918 influenza A virus (IAV) caused the worst flu pandemic in human history. Non-structural protein 1 (NS1) is an important virulence factor of the 1918 IAV and antagonizes host antiviral immune responses. NS1 increases virulence by activating phosphoinositide 3-kinase (PI3K) via binding to the p85β subunit of PI3K. Intriguingly, unlike the NS1 of other human IAV strains, 1918 NS1 hijacks another host protein, CRK, to form a ternary complex with p85β, resulting in hyperactivation of PI3K. However, the molecular basis of the ternary interaction between 1918 NS1, CRK, and PI3K remains elusive. Here, we report the structural and thermodynamic bases of the ternary interaction. We find that the C-terminal tail (CTT) of 1918 NS1 remains highly flexible in the complex with p85β. Thus, the CTT of 1918 NS1 in the complex with PI3K can efficiently hijack CRK. Notably, our study indicates that 1918 NS1 enhances its affinity to p85β in the presence of CRK, which might result in enhanced activation of PI3K. Our results provide structural insight into how 1918 NS1 hijacks two host proteins simultaneously.

scholarly journals Properties of H7N7 influenza A virus strain SC35M lacking interferon antagonist NS1 in mice and chickens

2007 ◽  
Vol 88 (5) ◽  
pp. 1403-1409 ◽  
Author(s):  
Georg Kochs ◽  
Iris Koerner ◽  
Lena Thiel ◽  
Sonja Kothlow ◽  
Bernd Kaspers ◽  
...  
Keyword(s):  
Influenza A Virus ◽  
Virulence Factor ◽  
Influenza A ◽  
Severe Disease ◽  
A549 Cells ◽  
Type I ◽  
Upper Respiratory Tract ◽  
Structural Protein ◽  
Wild Type ◽  
Ns1 Gene

Non-structural protein NS1 of influenza A virus counteracts the host immune response by blocking the synthesis of type I interferon (IFN). As deletion of the complete NS1 gene has to date been reported only in the human H1N1 strain A/PR/8/34, it remained unclear whether NS1 is a non-essential virulence factor in other influenza A virus strains as well. In this report, the properties of NS1-deficient mutants derived from strain SC35M (H7N7) are described. A mutant of SC35M that completely lacks the NS1 gene was an excellent inducer of IFN in mammalian and avian cells in culture and, consequently, was able to multiply efficiently only in cell lines with defects in the type I IFN system. Virus mutants carrying C-terminally truncated versions of NS1 were less powerful inducers of IFN and were attenuated less strongly in human A549 cells. Although attenuated in wild-type mice, these mutants remained highly pathogenic for mice lacking the IFN-regulated antiviral factor Mx1. In contrast, the NS1-deficient SC35M mutant was completely non-pathogenic for wild-type mice, but remained pathogenic for mice lacking Mx1 and double-stranded RNA-activated protein kinase (PKR). Wild-type SC35M, but not the NS1-deficient mutant virus, was able to replicate in the upper respiratory tract of birds, but neither virus induced severe disease in adult chickens. Altogether, this study supports the view that NS1 represents a non-essential virulence factor of different influenza A viruses.

scholarly journals NS1-mediated delay of type I interferon induction contributes to influenza A virulence in ferrets

2011 ◽  
Vol 92 (7) ◽  
pp. 1635-1644 ◽  
Author(s):  
Isabelle Meunier ◽  
Veronika von Messling
Keyword(s):  
Influenza A ◽  
Type I Interferon ◽  
Severe Disease ◽  
Type I ◽  
Lung Pathology ◽  
Structural Protein ◽  
Recombinant Viruses ◽  
Type I Ifns ◽  
Specific Strain

Interference of the influenza A virus non-structural protein NS1 with type I interferon (IFN) signalling has been characterized extensively in vitro. To assess the contribution of NS1 to the virulence of a specific strain, we generated recombinant USSR/90/77 viruses bearing the NS1 proteins of the attenuated strain PR/8/34 or the highly pathogenic strain 1918 ‘Spanish flu’, all belonging to the H1N1 subtype. In vitro, the extent of interference with type I IFN production exerted by the different NS1 proteins correlated with the reported virulence of the respective strain. Infection of ferrets with the recombinant viruses revealed that the presence of the 1918 NS1 resulted in a slightly more severe disease with generally higher clinical scores and increased lung pathology. Analysis of mRNA from nasal wash cells revealed that viruses carrying the 1918 and, to a lesser extent, USSR/90/77 NS1 proteins caused a delay in upregulation of type I IFNs compared with the NS1 PR/8/34-expressing virus, demonstrating the importance of NS1 for early host-response control and virulence.

scholarly journals SARS-CoV-2 launches a unique transcriptional signature from in vitro, ex vivo, and in vivo systems

2020 ◽  
Author(s):  
Daniel Blanco-Melo ◽  
Benjamin E. Nilsson-Payant ◽  
Wen-Chun Liu ◽  
Rasmus Møller ◽  
Maryline Panis ◽  
...  
Keyword(s):  
Influenza A Virus ◽  
Influenza A ◽  
Ex Vivo ◽  
Influenza Viruses ◽  
Model Systems ◽  
Type I ◽  
Transcriptional Signature ◽  
Syncytial Virus

ABSTRACTOne of the greatest threats to humanity is the emergence of a pandemic virus. Among those with the greatest potential for such an event include influenza viruses and coronaviruses. In the last century alone, we have observed four major influenza A virus pandemics as well as the emergence of three highly pathogenic coronaviruses including SARS-CoV-2, the causative agent of the ongoing COVID-19 pandemic. As no effective antiviral treatments or vaccines are presently available against SARS-CoV-2, it is important to understand the host response to this virus as this may guide the efforts in development towards novel therapeutics. Here, we offer the first in-depth characterization of the host transcriptional response to SARS-CoV-2 and other respiratory infections through in vitro, ex vivo, and in vivo model systems. Our data demonstrate the each virus elicits both core antiviral components as well as unique transcriptional footprints. Compared to the response to influenza A virus and respiratory syncytial virus, SARS-CoV-2 elicits a muted response that lacks robust induction of a subset of cytokines including the Type I and Type III interferons as well as a numerous chemokines. Taken together, these data suggest that the unique transcriptional signature of this virus may be responsible for the development of COVID-19.

scholarly journals A Herbal Mixture Formula of OCD20015-V009 Prophylactic Administration to Enhance Interferon-Mediated Antiviral Activity Against Influenza A Virus

2021 ◽  
Vol 12 ◽  
Author(s):  
Eun-Bin Kwon ◽  
You-Chang Oh ◽  
Youn-Hwan Hwang ◽  
Wei Li ◽  
Seok-Man Park ◽  
...  
Keyword(s):  
Antiviral Activity ◽  
Influenza A Virus ◽  
Influenza A ◽  
Type I ◽  
Protective Effects ◽  
Murine Macrophages ◽  
Prophylactic Administration ◽  
Pre Treatment

OCD20015-V009 is an herbal mix of water-extracted Ginseng Radix, Poria (Hoelen), Rehmanniae Radix, Adenophorae Radix, Platycodi Radix, Crataegii Fructus, and Astragali Radix. In this study, its in vitro and in vivo antiviral activity and mechanisms against the influenza A virus were evaluated using a GFP-tagged influenza A virus (A/PR/8/34-GFP) to infect murine macrophages. We found that OCD20015-V009 pre-treatment substantially reduced A/PR/8/34-GFP replication. Also, OCD20015-V009 pre-treatment increased the phosphorylation of type-I IFN-related proteins TBK-1 and STAT1 and the secretion of pro-inflammatory cytokines TNF-α and IL-6 by murine macrophages. Moreover, OCD20015-V009 prophylactic administration increased IFN-stimulated genes-related 15, 20, and 56 and IFN-β mRNA in vitro. Thus, OCD20015-V009 likely modulates murine innate immune response via macrophages. This finding is potentially useful for developing prophylactics or therapeutics against the influenza A virus. Furthermore, pre-treatment with OCD20015-V009 decreased the mortality of the mice exposed to A/PR/8/34-GFP by 20% compared to that in the untreated animals. Thus, OCD20015-V009 stimulates the antiviral response in murine macrophages and mice to viral infections. Additionally, we identified chlorogenic acid and ginsenoside Rd as the antiviral components in OCD20015-V009. Further investigations are needed to elucidate the protective effects of active components of OCD20015-V009 against influenza A viruses.

scholarly journals Influenza A Virus Negative Strand RNA is Translated for CD8+ T Cell Immunosurveillance

2018 ◽  
Author(s):  
Heather D. Hickman ◽  
Jacqueline W. Mays ◽  
James Gibbs ◽  
Ivan Kosik ◽  
Javier Magadan ◽  
...  
Keyword(s):  
T Cells ◽  
T Cell ◽  
Influenza A Virus ◽  
Influenza A ◽  
Cultured Cells ◽  
Rna Virus ◽  
Cd8 T Cell ◽  
Negative Strand

AbstractTo probe the limits of CD8+ T cell immunosurveillance, we inserted the model peptide SIINFEKL into influenza A virus (IAV) negative strand gene segments. Although IAV genomic RNA is widely considered as non-coding, there is a conserved, relatively long open reading frame present in the genomic strand of segment eight, encoding a potential protein termed NEG8. The biosynthesis of NEG8 from IAV has yet to be demonstrated. While we failed to detect NEG8 protein expression in IAV infected cells, cell surface Kb-SIINFEKL complexes are generated when SIINFEKL is genetically appended to the predicted COOH-terminus of NEG8, as shown by activation of OT-I T cells in vitro and in vivo. Moreover, recombinant IAV encoding SIINFEKL embedded in the negative strand of the NA-stalk coding sequence also activates OT-I T cells in vivo. Together, our findings demonstrate both the translation of sequences on the negative strand of a single stranded RNA virus and its relevance anti-viral immunosurveillance.SignificanceEvery gene encodes complementary information on the opposite strand that can potentially be used for immunosurveillance. In this study, we show that the influenza A virus “non-coding” strand translated into polypeptides during a viral infection of either cultured cells or mice that can be recognized by CD8+ T cells. Our findings raise the possibility that influenza virus uses its negative strand to generate proteins useful to the virus. More generally, it adds to a growing literature showing that immunosurveillance extends to gene sequences generally thought not to be converted into proteins. The relevance of translating this “dark” information extends from viral immunity to cancer immunotherapy and autoimmunity.

scholarly journals Specific Mutations in the PB2 Protein of Influenza A Virus Compensate for the Lack of Efficient Interferon Antagonism of the NS1 Protein of Bat Influenza A-Like Viruses

2018 ◽  
Vol 92 (7) ◽  
Author(s):  
Teresa Aydillo ◽  
Juan Ayllon ◽  
Amzie Pavlisin ◽  
Carles Martinez-Romero ◽  
Shashank Tripathi ◽  
...  
Keyword(s):  
Amino Acid ◽  
Influenza A Virus ◽  
Influenza A ◽  
Single Amino Acid ◽  
Type I ◽  
Ns1 Protein ◽  
Influenza A Viruses ◽  
Basic Biology

ABSTRACTRecently, two new influenza A-like viruses have been discovered in bats, A/little yellow-shouldered bat/Guatemala/060/2010 (HL17NL10) and A/flat-faced bat/Peru/033/2010 (HL18NL11). The hemagglutinin (HA)-like (HL) and neuraminidase (NA)-like (NL) proteins of these viruses lack hemagglutination and neuraminidase activities, despite their sequence and structural homologies with the HA and NA proteins of conventional influenza A viruses. We have now investigated whether the NS1 proteins of the HL17NL10 and HL18NL11 viruses can functionally replace the NS1 protein of a conventional influenza A virus. For this purpose, we generated recombinant influenza A/Puerto Rico/8/1934 (PR8) H1N1 viruses containing the NS1 protein of the PR8 wild-type, HL17NL10, and HL18NL11 viruses. These viruses (r/NS1PR8, r/NS1HL17, and r/NS1HL18, respectively) were tested for replication in bat and nonbat mammalian cells and in mice. Our results demonstrate that the r/NS1HL17 and r/NS1HL18 viruses are attenuatedin vitroandin vivo. However, the bat NS1 recombinant viruses showed a phenotype similar to that of the r/NS1PR8 virus in STAT1−/−human A549 cells and mice, bothin vitroandin vivosystems being unable to respond to interferon (IFN). Interestingly, multiple mouse passages of the r/NS1HL17 and r/NS1HL18 viruses resulted in selection of mutant viruses containing single amino acid mutations in the viral PB2 protein. In contrast to the parental viruses, virulence and IFN antagonism were restored in the selected PB2 mutants. Our results indicate that the NS1 protein of bat influenza A-like viruses is less efficient than the NS1 protein of its conventional influenza A virus NS1 counterpart in antagonizing the IFN response and that this deficiency can be overcome by the influenza virus PB2 protein.IMPORTANCESignificant gaps in our understanding of the basic features of the recently discovered bat influenza A-like viruses HL17NL10 and HL18NL11 remain. The basic biology of these unique viruses displays both similarities to and differences from the basic biology of conventional influenza A viruses. Here, we show that recombinant influenza A viruses containing the NS1 protein from HL17NL10 and HL18NL11 are attenuated. This attenuation was mediated by their inability to antagonize the type I IFN response. However, this deficiency could be compensated for by single amino acid replacements in the PB2 gene. Our results unravel a functional divergence between the NS1 proteins of bat influenza A-like and conventional influenza A viruses and demonstrate an interplay between the viral PB2 and NS1 proteins to antagonize IFN.

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